If he wins, Barack Obama is going to be sworn in on a Koran instead of the Bible. Trig isn't Sarah Palin's baby, it's her daughter Bristol's. Obama refuses to say the Pledge of Allegiance. Here's the list of books Palin wanted to ban from the library.

All these claims -- none of them true -- turned up in the email inboxes of millions of Americans this summer. In spite of both campaigns' efforts to correct the record about their candidates, the rumors linger on, and spread.

False claims are not new to American presidential politics. What makes this election different is the culture of instantaneousness made possible by the Internet and the cell phone.

Many more people forward emails about political issues, click on links to political YouTube videos, and comment on political blogs than did so four years ago. According to the Pew Internet Trust, more Americans had sought political information online by June of this year than had done so during the entire 2004 campaign.

The same technologies that make information sharing so easy also make fact-checking easy. A Google search for any of the four rumors, just as I stated them, returns mostly explanations of why they are false. The politically neutral sites Factcheck.org and snopes.com debunk these stories and many others.

Yet it is a deep irony of digital revolution that the connectedness it has created encourages us to act rather than to think, even though the technology connects us to the truth as well as to each other.

We use cell phones and the Internet to stay in touch with our peers, to share and to coordinate our activities. We could also use it to research dubious claims, but why do that during our chat time? Why pause to check out a rumor, when our friend Mary might get it from someone else before we have a chance to forward it to her? The Internet is empowering, but we too often use its power to make fools of ourselves.

So what? Most of these bogus stories get sorted out eventually, don't they? Isn't the Internet a big marketplace of ideas? As citizens of an enlightened democracy, shouldn't we have confidence that the truth will ultimately prevail?

Perhaps not.

The factoids are not just instant; they are atomic. We keep emails short because people have to process so many of them. Instant messages and "tweets" are rarely more than a few words. They arrive without provenance, historical context, or the other side of the story. When we pass them on to our friends, they explode into a cloud of information particles, as identical as hydrogen atoms and as pervasive as nuclear fallout. And sometimes as destructive.

On Sept. 7, a Bloomberg News web site posted a headline about the bankruptcy of United Airlines. Within minutes, the company's stock dropped from $11 to $3, wiping out a billion dollars in worth. The headline was erroneous. A news story from 2002, when United actually had declared bankruptcy, inexplicably crawled out of its digital cave on Sept. 6 and turned up as a Google search result. Human negligence (anyone reading the story itself would have realized that it was not current) and urgency to spread the word (anyone delaying a response for a few seconds might lose millions of dollars) combined to produce the implosion.

The story of United Airlines has a particularly unsettling angle: Those seeing the bogus news blip would almost certainly have felt compelled to sell the stock, even if they knew the story was false. We all know that the whole world now reacts to Internet news, sometimes automatically. Once the item was available on a popular site, the catastrophe was inevitable.

Weirdly, Bloomberg has no liability. The law protects this newspaper if someone posts a libelous comment on a blog. The same statute protects any site that posts someone else's misinformation.

With human judgment so eclipsed by responses to atomized, instant data, can there be much doubt that intentional manipulations -- of the markets, and of the electorate -- should be expected?

Of the questions facing us about digital culture, the most troubling is this: Will the interactivity of the media, the atomization of knowledge, and the premium on rapid response result in a collective loss of wisdom, judgment, and perspective?

Opinions differ among the experts (some self-appointed). Dystopians such as Mark Bauerlein, author of "The Dumbest Generation," fear for the future of American democracy, if the electorate, caught up in instantaneous frivolity, fails to learn the deeper principles of republican government. Cautious utopians such as John Palfrey, coauthor of "Born Digital," find that digital culture is different, not worse, and that its bright side far outshines the dark. A host of other books with titles like "Distracted" and "Everything Bad For You Is Good" weigh in on one side of the debate or the other.

But few dispute the U.S. government statistics that Americans are reading fewer books than they used to, and that the decline is particularly sharp among the young.

Will screen-reading suffice to create a thoughtful, analytical, educated citizenry, capable of sharing responsibility for the long-term welfare of the nation? I, for one, doubt it.

Harry Lewis is a professor of computer science at Harvard University and a fellow of the Berkman Center for Internet and Society. He is co-author of "Blown to Bits: Your Life, Liberty, and Happiness After the Digital Explosion."